Portal:Volcanoes
The Volcanoes portal
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes resulting from divergent tectonic activity are usually non-explosive whereas those resulting from convergent tectonic activity cause violent eruptions. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift, the Wells Gray-Clearwater volcanic field, and the Rio Grande rift in North America. Volcanism away from plate boundaries most likely arises from upwelling diapirs from the core–mantle boundary called mantle plumes, 3,000 kilometres (1,900 mi) deep within Earth. This results in hotspot volcanism or intraplate volcanism, in which the plume may cause thinning of the crust and result in a volcanic island chain due to the continuous movement of the tectonic plate, of which the Hawaiian hotspot is an example. Volcanoes are usually not created at transform tectonic boundaries where two tectonic plates slide past one another.
Volcanoes, based on their frequency of eruption or volcanism, are referred to as either active or extinct. Active volcanoes have a history of volcanism and are likely to erupt again while extinct ones are not capable of eruption at all as they have no magma source. “Dormant” volcanoes have not erupted in a long time- generally accepted as since the start of the Holocene, about 12000 years ago- but may erupt again. These categories aren't entirely uniform; they may overlap for certain examples.
Large eruptions can affect atmospheric temperature as ash and droplets of sulfuric acid obscure the Sun and cool Earth's troposphere. Historically, large volcanic eruptions have been followed by volcanic winters which have caused catastrophic famines.
Other planets besides Earth have volcanoes. For example, volcanoes are very numerous on Venus. Mars has significant volcanoes. In 2009, a paper was published suggesting a new definition for the word 'volcano' that includes processes such as cryovolcanism. It suggested that a volcano be defined as 'an opening on a planet or moon's surface from which magma, as defined for that body, and/or magmatic gas is erupted.'
This article mainly covers volcanoes on Earth. See § Volcanoes on other celestial bodies and cryovolcano for more information. (Full article...)
Selected article -
Cerro Azul (Spanish pronunciation: [ˈsero aˈsul], blue hill in Spanish), sometimes referred to as Quizapu, is an active stratovolcano in the Maule Region of central Chile, immediately south of Descabezado Grande. Part of the South Volcanic Zone of the Andes, its summit is 3,788 meters (12,428 ft) above sea level, and is capped by a summit crater that is 500 meters (1,600 ft) wide and opens to the north. Beneath the summit, the volcano features numerous scoria cones and flank vents.
Cerro Azul is responsible for several of South America's largest recorded eruptions, in 1846 and 1932. In 1846, an effusive eruption formed the vent at the site of present-day Quizapu crater on the northern flank of Cerro Azul and sent lava flowing down the sides of the volcano, creating a lava field 8–9 square kilometres (3–3.5 square miles) in area. Phreatic and Strombolian volcanism between 1907 and 1932 excavated this crater. In 1932, one of the largest explosive eruptions of the 20th century occurred at Quizapu Crater and sent 9.5 cubic kilometers (2.3 cu mi) of ash into the atmosphere. The volcano's most recent eruption was in 1967. (Full article...)
Did you know
- ...that the 1980 Mount St. Helens eruption (pictured) in Washington was the first major volcanic eruption to occur in the U.S. since the 1915 eruption of Lassen Peak in California?
- ...that the evolution of Hawaiian volcanoes ends with the Guyot Stage, and that most, if not all, the volcanoes west of Kure Atoll are guyots?
- ...that the Irazú Volcano in Costa Rica erupted violently in 1963, on the day U.S. President John F. Kennedy arrived in the country for a state visit?
- ...that Ferdinandea was a volcanic island near Sicily which was claimed by four countries when it appeared in 1831, but was destroyed by erosion less than a year later?
- ...that the Iceland hotspot is partly responsible for the frequent volcanic eruptions and geothermal activity experienced in Iceland?
- ...that the only active volcano in South Asia is on Barren Island, one of India's Andaman Islands?
- ...that Imbabura is an inactive stratovolcano in northern Ecuador which is revered in local folklore as a protective parent?
- ..that one submarine volcano located in Banda Sea of Indonesia is called the Emperor of China?
General images
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Lava-flooded craters and large expanses of smooth volcanic plains on Mercury (from List of extraterrestrial volcanoes) -
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The high initial temperatures of silicate lavas mean that they emit visible light before cooling. (from Volcanism) -
Diagram of Peléan eruption. (key: 1. Ash plume 2. Volcanic ash rain 3. Lava dome 4. Volcanic bomb 5. Pyroclastic flow 6. Layers of lava and ash 7. Stratum 8. Magma conduit 9. Magma chamber 10. Dike) Click for larger version. (from Volcanic eruption) -
2016 eruption of Mount Sinabung (from Volcanic eruption) -
Satellite measurements of ash and aerosol emissions from Mount Pinatubo. (from Timeline of volcanism on Earth) -
Diagram of a Surtseyan eruption. (key: 1. Water vapor cloud 2. Compressed ash 3. Crater 4. Water 5. Layers of lava and ash 6. Stratum 7. Magma conduit 8. Magma chamber 9. Dike) Click for larger version. (from Volcanic eruption) -
Diagram of a Vulcanian eruption. (key: 1. Ash plume 2. Lapilli 3. Lava fountain 4. Volcanic ash rain 5. Volcanic bomb 6. Lava flow 7. Layers of lava and ash 8. Stratum 9. Sill 10. Magma conduit 11. Magma chamber 12. Dike) Click for larger version. (from Volcanic eruption) -
Sulfur dioxide emissions by volcanoes. Mount Pinatubo: 20 million tons of sulfur dioxide. (from Timeline of volcanism on Earth) -
MLO transmission ratio - Solar radiation reduction due to volcanic eruptions (from Timeline of volcanism on Earth) -
Distribution of selected hotspots. The numbers in the figure are related to the listed hotspots on Hotspot (geology). (from Timeline of volcanism on Earth) -
Sarychev Peak: the sulphur dioxide cloud generated by the eruption on June 12, 2009 (in Dobson units). (from Timeline of volcanism on Earth) -
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Diagram of a Hawaiian eruption. (key: 1. Ash plume 2. Lava fountain 3. Crater 4. Lava lake 5. Fumaroles 6. Lava flow 7. Layers of lava and ash 8. Stratum 9. Sill 10. Magma conduit 11. Magma chamber 12. Dike) Click for larger version. (from Volcanic eruption) -
VEI and ejecta volume correlation (from Timeline of volcanism on Earth)
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Some of the eruptive structures formed during volcanic activity (counterclockwise): a Plinian eruption column, Hawaiian pahoehoe flows, and a lava arc from a Strombolian eruption (from Volcanic eruption) -
Eruption of mud at Dashgil mud volcano in Gobustan, Azerbaijan (from Volcanism) -
Location of Mount Pinatubo, showing area over which ash from the 1991 eruption fell. (from Timeline of volcanism on Earth) -
NASA, Global Dimming - El Chichon, VEI 5; Pinatubo, VEI 6. (from Timeline of volcanism on Earth) -
Phreatic explosion captured at the Main Crater of Taal Volcano in January 2020, from an installed IP camera of the Philippine Institute of Volcanology and Seismology (PHIVOLCS) monitoring the volcano. (from Decade Volcanoes) -
Diagram of a phreatic eruption. (key: 1. Water vapor cloud 2. Magma conduit 3. Layers of lava and ash 4. Stratum 5. Water table 6. Explosion 7. Magma chamber) (from Volcanic eruption) -
Diagram of a Submarine eruption. (key: 1. Water vapor cloud 2. Water 3. Stratum 4. Lava flow 5. Magma conduit 6. Magma chamber 7. Dike 8. Pillow lava) Click to enlarge. (from Volcanic eruption) -
A gentle, or effusive, volcanic eruption, in which liquid material (lava) gently flows from a vent, in this case in south-eastern Hawai’i island (from Volcanism) -
21 April 1990 eruptive column from Redoubt Volcano, as viewed to the west from the Kenai Peninsula (from Volcanic eruption) -
Mount Lamington following the devastating 1951 eruption (from Volcanic eruption) -
The final eruptions in the creation of Banks Peninsula in New Zealand occurred about 9 million years ago. (from Timeline of volcanism on Earth) -
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Diagram of a Plinian eruption. (key: 1. Ash plume 2. Magma conduit 3. Volcanic ash rain 4. Layers of lava and ash 5. Stratum 6. Magma chamber) Click for larger version. (from Volcanic eruption) -
Some features of volcanism found in Earth's crust (from Volcanism) -
Satellite animation of the initial ash plume and shockwave of the 2022 Hunga Tonga–Hunga Ha’apai eruption and tsunami. The massive explosive eruption was hundreds of times more powerful than the atomic bomb dropped on Hiroshima. (from Volcanism) -
An example of the lava arcs formed during Strombolian activity. This image is of Stromboli itself. (from Volcanic eruption) -
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A major eruption of Gran Canaria took place around 14 million years ago. (from Timeline of volcanism on Earth) -
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Diagram of a Strombolian eruption. (key: 1. Ash plume 2. Lapilli 3. Volcanic ash rain 4. Lava fountain 5. Volcanic bomb 6. Lava flow 7. Layers of lava and ash 8. Stratum 9. Dike 10. Magma conduit 11. Magma chamber 12. Sill) Click for larger version. (from Volcanic eruption) -
TOMS sulfur dioxide from the June 15, 1991 eruption of Mount Pinatubo. (from Timeline of volcanism on Earth) -
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Colima Volcano eruption column, December 2016 (from Decade Volcanoes) -
Lahar flows from the 1985 eruption of Nevado del Ruiz, which totally destroyed Armero in Colombia (from Volcanic eruption) -
Cross section diagram of Earth showing some settings for volcanism on the planet (from Volcanism) -
Olympus Mons (Latin, "Mount Olympus"), located on the planet Mars, is the tallest known mountain in the Solar System. (from Volcanism) -
A diagram of a Subglacial eruption. (key: 1. Water vapor cloud 2. Crater lake 3. Ice 4. Layers of lava and ash 5. Stratum 6. Pillow lava 7. Magma conduit 8. Magma chamber 9. Dike) Click for larger version. (from Volcanic eruption) -
Diagrammatic representation of a plume on Enceladus (from Volcanism) -
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Selected biography -
Catherine Hickson (born 1955) is a Canadian volcanologist, formerly with the Geological Survey of Canada, part of Natural Resources Canada. Since 2014, she has been the chief operating officer for Dajin Resources Corp. and president, Tuya Terra Geo Corp. Hickson studied at the University of British Columbia and received her PhD in geology and volcanology in 1987. (Full article...)
Selected picture
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The small town of Ortahisar in Cappadocia, Turkey. The area is covered in soft volcanic rock, which villagers have carved out to form houses, monasteries, and other structures.
Selected quote
"Do we need to bring a sleeping bag, or will the volcano keep us warm at night?"
— Documentary producer at Mount Etna, 2000.
Related portals
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Featured work and other approved content
Featured articles: 1980 eruption of Mount St. Helens • 2007–2008 Nazko earthquakes • Amchitka • Armero tragedy • Craters of the Moon National Monument and Preserve • Cerro Azul (Chile volcano) • David A. Johnston • Enceladus (moon) • Geology of the Lassen volcanic area • Io (moon) • Kamaʻehuakanaloa Seamount • Mauna Kea • Mauna Loa • Metacomet Ridge • Mono-Inyo Craters • Mount Cayley volcanic field • Mount St. Helens • Mount Tambora • Nevado del Ruiz • Surtsey • The Volcano (British Columbia) • Triton (moon) • Upper and Lower Table Rock • Volcanism on Io • Volcano (South Park) • Yellowstone National Park
Featured lists: List of volcanoes in Indonesia • List of volcanoes in the Hawaiian – Emperor seamount chain • List of largest volcanic eruptions
Featured pictures: There are currently 43 volcano-related Featured pictures. A full gallery can be seen here.
Good articles: Abyssal plain • Amak Volcano • Anahim hotspot • Axial Seamount • Ben Nevis • Bowie Seamount • Crater Lake • Davidson Seamount • Ferdinandea • Gareloi Volcano • Geyser • Glacier Peak • Hawaii hotspot • Hualālai • Kohala (mountain) • Lake Toba • Minoan eruption • Mount Adams (Washington) • Mount Bailey • Mount Baker • Mount Cleveland (Alaska) • Mount Edziza volcanic complex • Mount Garibaldi • Mount Hood • Mount Kenya • Mount Rainier • Mount Redoubt • Mount Tehama • Mount Thielsen • Mount Vesuvius • Peter I Island • Roxy Ann Peak • Rùm • Sakurajima • Sangay • Silverthrone Caldera • Staffa • Types of volcanic eruptions • Volcanic ash • Weh Island • Wells Gray-Clearwater volcanic field • Yamsay Mountain
Valued pictures: A gallery of volcano-related valued pictures can be seen here.
What you can do
- Add the {{WikiProject Volcanoes}} message box to talk pages of articles within the scope of this project, including appropriate assessments, if needed.
- Add appropriate volcano type categories to articles, and verify the accuracy of any existing categories. See the section "Categorization" below.
- Add {{infobox mountain}} to articles if needed and missing, and add volcano-related fields to existing infoboxes if these are missing.
- Expand volcano articles which are stubs, especially by adding photos and (most importantly) proper references.
- Help improve articles related to Hawaiian and Canadian volcanism by joining the Hawaiian and Canadian workgroups.
- Improve some of the project's most visible articles.
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